"On the day the entire island of Ireland is looking at Derry and reflecting in the glow of Lonely Planet stating that Derry is the fourth best city in the world to visit in 2013, we have people hell-bent on disrupting that positive image.

"These people need to step aside and let us get on with making that positive contribution. I urge anybody to pass whatever information they know about this to the police. Derry cannot afford to have people running around with guns and firing them into people's homes."